UNASSIGNED: To raise awareness about the increasing incidence of superfetation and heterotopic pregnancy in patients with ovarian induction, their insidious symptoms of abdominal pain, anemia, and hemodynamic instability in early pregnancy, and the usefulness of transvaginal ultrasound (TVUS) and quantitative beta human chorionic gonadotrophin (b-hCG) for diagnosis.
UNASSIGNED: Superfetation, occurrence of ovulation, fertilization, and implantation during an ongoing pregnancy and heterotopic pregnancy (HP) simultaneous presence of intrauterine and extrauterine pregnancies are infrequent phenomena. We report a case where both coexisted, challenges in diagnosis and management and association with the widespread use of assisted reproductive technologies (ARTs). A 32-year-old woman, who previously underwent ovulation induction therapy, presented with abdominal pain at 8 weeks pregnancy according to her last menstrual period. The patient had high quantitative serum beta-human chorionic gonadotropin (b-hCG) (30,883 mIU/mL). She was vitally stable and not anemic. Transvaginal ultrasound (TVUS) revealed two pregnancies at different gestational ages: an intrauterine pregnancy at 5 weeks and 3 days, and a right intact tubal ectopic pregnancy at 10 weeks and 5 days. Superfetation resulting in HP was then diagnosed. Subsequently, the patient underwent right laparoscopic salpingectomy. The intrauterine pregnancy progressed normally, resulting in delivery of a healthy full-term neonate via Cesarean section at 38 weeks. Superfetation is typically rare from suppression of follicular development and ovulation during pregnancy. Various theories have been proposed to explain its etiology, including polyovulation, delayed blastocyst implantation, and abnormal estrogen and b-hCG surges. In superfetation, an embryo resulting from a previous conception coexists with another embryo, either intrauterine, resulting in diamniotic dizygotic twins with significantly different gestational ages, or extrauterine resulting in HP. Despite being particularly challenging to diagnose because its presenting symptoms can overlap with those of other more common clinical conditions in early pregnancy, HP is increasingly seen with ARTs. In addition, the treatment of HP is versatile, ranging from expectant management to laparoscopic surgery. High level of suspicion for HP and superfetation is crucial in patients who, after ART, present with abdominal pain, hemodynamic instability, or anemia. Additionally, patients planning to undergo subsequent ART cycles should be thoroughly screened with b-hCG and TVUS to exclude an ongoing intrauterine or extrauterine pregnancy.

Heterotopic pregnancy is an extremely rare condition in which an intrauterine and an extrauterine pregnancy co-exist. In spontaneous conceptions, heterotopic pregnancy occurs in only 1/30 000 pregnancies. The treatment of heterotopic pregnancy must be as minimally invasive as possible to preserve the development of the intrauterine pregnancy. Superfetation, defined as the coexistence of 2 or more foetuses of different gestational ages, remains particularly exceptional and poorly explained (second ovulation? embryonic diapause?). Here, we present an extremely rare case of a spontaneous heterotopic evolutive pregnancy with superfetation, consisting of an embryo in the pouch of Douglas estimated at 8 + 1 weeks of gestation (WG) and a progressive intrauterine pregnancy estimated at 5 + 4 WG. We treated the extrauterine pregnancy with an intra-cardiac injection of potassium chloride echo-guided via the vaginal route, and the patient then underwent exploratory laparoscopy 9 days later and lavage and aspiration of the abdominal heterotopic pregnancy due to pain and biological inflammatory syndrome probably caused by pelvic mass syndrome and peritoneal irritation from the foetal necrosis. She has not yet given birth and is currently at 36 WG.

Superfetation is a very rare occurrence. In the context of assisted reproduction, it has been reported only as an intrauterine pregnancy after ovarian stimulation and/or embryo transfer in the presence of an undiagnosed ectopic pregnancy. Here we report a case of a 27-year-old anovulatory patient, gravida 1 para 1, who underwent two frozen-thawed single-blastocyst transfers in separate cycles. The patient reported that 12 days after the first transfer, she had menstrual bleeding and stopped her estradiol and progesterone supplementation without undergoing a blood human chorionic gonadotropin (βhCG) test. At her request, a second cycle was immediately initiated, with endometrial thickness measuring 4 mm. Eleven days after the second transfer, the βhCG value was inappropriately high. A right tubal pregnancy corresponding to 8 gestational weeks was diagnosed. Laparoscopy revealed a prominent right tubal pregnancy in addition to a significantly smaller left tubal pregnancy. The discordant tubal pregnancies were confirmed histologically. To our knowledge, superfetation involving a second ectopic pregnancy coexistent with a first, contralateral ectopic pregnancy consequent to consecutive in vitro fertilization procedures has not previously been described in the medical literature. This case emphasizes the importance of routine βhCG testing after every IVF cycle, even if apparently unsuccessful.

The causes and consequences of the evolution of placentotrophy (post-fertilization nutrition of developing embryos of viviparous organisms by means of a maternal placenta) in non-mammalian vertebrates are still not fully understood. In particular, in the fish family Poeciliidae there is an evolutionary link between placentotrophy and superfetation (ability of females to simultaneously bear embryos at distinct developmental stages), with no conclusive evidence for which of these two traits facilitates the evolution of more advanced degrees of the other. Using a robust phylogenetic comparative method based on Ornstein-Uhlenbeck models of adaptive evolution and data from 36 poeciliid species, we detected a clear causality pattern. The evolution of extensive placentotrophy has been facilitated by the preceding evolution of more simultaneous broods. Therefore, placentas became increasingly complex as an adaptive response to evolutionary increases in the degree of superfetation. This finding represents a substantial contribution to our knowledge of the factors that have shaped placental evolution in poeciliid fishes.

Superfetation, the ability to carry several overlapping broods at different developmental stages, has evolved independently multiple times within the live-bearing fish family Poeciliidae. Even though superfetation is widespread among poeciliids, its evolutionary advantages remain unclear. Theory predicts that superfetation should increase polyandry by increasing the probability that temporally overlapping broods are fertilized by different fathers. Here, we test this key prediction in two poeciliid species that each carry two temporally overlapping broods: Poeciliopsis retropinna and P. turrubarensis. We collected 25 females per species from freshwater streams in South-Eastern Costa Rica and assessed multiple paternity by genotyping all their embryos (420 embryos for P. retropinna; 788 embryos for P. turrubarensis) using existing and newly developed microsatellite markers. We observed a high frequency of unique sires in the simultaneous, temporally overlapping broods in P. retropinna (in 56% of the pregnant females) and P. turrubarensis (79%). We found that the mean number of sires within females was higher than the number of sires within the separate broods (2.92 sires within mothers vs. 2.36 within separate broods in P. retropinna; and 3.40 vs 2.56 in P. turrubarensis). We further observed that there were significant differences in the proportion of offspring sired by each male in 42% of pregnant female P. retropinna and 65% of female P. turrubarensis; however, this significance applied to only 9% and 46% of the individual broods in P. retropinna and P. turrubarensis, respectively, suggesting that the unequal reproductive success of sires (i.e. reproductive skew) mostly originated from differences in paternal contribution between, rather than within broods. Together, these findings tentatively suggest that superfetation may promote polyandry and reproductive skew in live-bearing fishes.

Background: Heterotopic pregnancy is an exceedingly rare condition in which an intrauterine and extrauterine pregnancy coexist. Superfetation refers to the coexistence of 2 or more fetuses of different gestational ages as a result of ovulation, fertilization, and implantation during an ongoing pregnancy. We present a case of heterotopic triplet pregnancy with a difference in gestational age by crown rump length of more than 1 week between the twin intrauterine pregnancy and the singleton tubal ectopic. Case Report: A 31-year-old gravida 3, para 2002 presented to the emergency department with abdominal pain at 9 weeks 2 days\' gestation dated by last menstrual period, consistent with ultrasound. She was discharged home with a diagnosis of ruptured hemorrhagic cyst but returned 4 days later with ruptured tubal ectopic pregnancy measuring 9 weeks\' gestation and ongoing twin gestation measuring 10 weeks 1 day. She was taken to the operating room for laparoscopic salpingectomy, and ectopic pregnancy was confirmed on tissue diagnosis. Conclusion: Heterotopic pregnancy presents a diagnostic challenge for obstetricians/gynecologists. Superfetation has never been demonstrably proven in humans but has been suggested in the literature. This report adds to the literature that perhaps superfetation can be artificially induced in humans in the presence of assisted reproductive technologies.

Serum progesterone levels performed prior to oocyte pick-up is commonly used to guide embryo transfer in in-vitro fertilization (IVF) cycles, as elevated levels can negatively influence pregnancy outcomes. However, levels associated with normal pregnancies should trigger clinicians to consider alternative causes such as a pre-existing pregnancy. We report a case of a 37-year-old patient who underwent controlled ovarian hyperstimulation in a gonadotrophin-releasing hormone antagonist cycle while having an undetected early pregnancy. No oocytes were retrieved at oocyte retrieval despite adequate follicular responses. Her serum progesterone level on the day of her trigger injection was 57.8 nmol/L. She was found to have a pregnancy of unknown location, detected 3 weeks after her oocyte retrieval and was subsequently treated with systemic methotrexate.

A presumably rare, but naturally occurring twinning event is heteropaternal (HP) twinning. HP twinning results from superfecundation, a reproductive process in which offspring share their mothers, but not their fathers. The resulting twins share an average of 25% of their segregating genes, the same proportion as half-siblings. A recently identified case of HP opposite-sex twins was confirmed by DNA analyses available for the twins and for multiple family members. Thus, an exceptional feature of the current report is the inclusion of data for the twins\' brothers, sisters, half-siblings, nieces, nephews and cousins, as well as several parent-child pairs. HP twins often go unnoticed so are typically classified as dizygotic (DZ) twins whose genetic overlap is 50%, on average, but varies across traits. As a unique category of non-identical twins, HP twinning is important to acknowledge as it may affect twins\' physical resemblance, behavioral similarity, personal identity, family relations and health concerns. While including HP pairs in twin research has been shown to have minimal impact on heritability estimates, it could conceivably affect the outcomes of small-scale studies. Given a lack of consistent and known prevalence, case studies provide valuable knowledge regarding the occurrence of HP twinning. Its implications for forensic science and for twin research are considerable.

How and why complex organs evolve is generally lost to history. The mammalian placenta, for example, was derived from a single common ancestor that lived over 100 million years ago.1-3 Therefore, the selective factors favoring this complex trait remain obscure. Species in the live-bearing fish family Poeciliidae have independently evolved placentas numerous times while retaining closely related non-placental sister species.4-7 This provides the raw material to test alternative hypotheses for the evolution of the placenta. We assemble an extensive species-level dataset on reproductive mode, life histories, and habitat, and then implement phylogenetic comparative methods to test adaptive hypotheses for the evolution of the placenta. We find no consistent family-wide associations between placentation and habitat. However, placental species exhibit significantly reduced reproductive allotment and have a higher likelihood of exhibiting superfetation (the ability to gestate multiple broods at different developmental stages). Both features potentially increase body streamlining and enhance locomotor performance during pregnancy, possibly providing selective advantage in performance-demanding environments such as those with high predation or fast water flow. Furthermore, we found significant interactions between body size and placentation for offspring size and fecundity. Relative to non-placental species, placentation is associated with higher fecundity and smaller offspring size in small-bodied species and lower fecundity and larger offspring size in large-bodied species. This pattern suggests that there may be two phenotypic adaptive peaks, corresponding to two selective optima, associated with placentation: one represented by small-bodied species that have fast life histories, and the second by large-bodied species with slow life histories.

Heteropaternal superfecundation (HS) refers to the fertilization of two or more oocytes by spermatozoa from different male partners during the polyovulatory period. The present study reported a newly discovered case of HS in the 10th week of gestation, in a case of disputed paternity involving a pair of female twins and two alleged fathers (AF1 and AF2), based on a custom-designed microhap sequencing assay and R package relMix for data interpretation. The results suggested that the twins had different biological fathers, e.g., HS, and indicated the paternity of AF1 in relation to one of the twins while excluding AF2 with regard to both twins. Standard short tandem repeat (STR) analysis was employed to confirm the paternity of the heteropaternal twins. The reported case indicates that HS may occur in paternity cases with dizygotic twins, and microhap, as a novel type of highly polymorphic marker proved to be suitable for mixture deconvolution, should be able to resolve this question effectively and noninvasively at the early stage of pregnancy.